import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool _isDarkMode = false;

  void _toggleTheme() {
    setState(() {
      _isDarkMode = !_isDarkMode;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme:
          _isDarkMode
              ? ThemeData.dark().copyWith(
                colorScheme: ColorScheme.dark(
                  primary: Colors.blueGrey[800]!,
                  secondary: Colors.blueGrey[600]!,
                ),
              )
              : ThemeData.light().copyWith(
                colorScheme: ColorScheme.light(
                  primary: Colors.blue[400]!,
                  secondary: Colors.lightBlue[300]!,
                ),
              ),
      home: MyHomePage(
        title: 'Flutter Demo Home Page',
        toggleTheme: _toggleTheme,
        isDarkMode: _isDarkMode,
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({
    super.key,
    required this.title,
    required this.toggleTheme,
    required this.isDarkMode,
  });

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;
  final VoidCallback toggleTheme;
  final bool isDarkMode;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          //
          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
          // action in the IDE, or press "p" in the console), to see the
          // wireframe for each widget.
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text('You have pushed the button this many times:'),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
            const SizedBox(height: 20),
            ElevatedButton(
              onPressed: widget.toggleTheme,
              child: Text(widget.isDarkMode ? '白天模式' : '黑夜模式'),
            ),
          ],
        ),
      ),
      floatingActionButton: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            colors:
                widget.isDarkMode
                    ? [Colors.blueGrey[800]!, Colors.blueGrey[600]!]
                    : [Colors.blue[400]!, Colors.lightBlue[300]!],
          ),
          borderRadius: BorderRadius.circular(30),
        ),
        child: FloatingActionButton(
          onPressed: _incrementCounter,
          tooltip: 'Increment',
          backgroundColor: Colors.transparent,
          elevation: 0,
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}
